JP2016539258A - Polylactic acid blend nonwoven fabric with improved flexibility and method for producing the same - Google Patents

Abstract

The present invention relates to a polylactic acid blend nonwoven fabric having improved flexibility and a method for producing the same. In the total weight of the polymer mixture, the weight of polylactic acid is 10-80% by weight, the weight of polypropylene is 10-89% by weight, the weight of dispersant is 1-7% by weight, flexible The weight of the agent is 1 to 3% by weight, and the total weight of the nonwoven fabric is 10 to 100 gsm. The polylactic acid blend nonwoven fabric with improved flexibility according to the present invention and the method for producing the same according to the present invention have a specific coefficient of addition of a specific softener to reduce the coefficient of friction on the surface of the nonwoven fabric. In addition to the low carbon emission characteristics of conventional polypropylene / polylactic acid nonwoven fabrics, it solves the disadvantage of inflexibility due to the hard properties peculiar to polylactic acid, and at the time of mixing and spinning using a dispersant, By specifying and adjusting the manufacturing process conditions, polylactic acid and polypropylene are uniformly mixed, and spinning and nonwoven fabric are formed to increase productivity and eliminate conventional problems.

Description

  The present invention relates to a polylactic acid blend nonwoven fabric having improved flexibility and a method for producing the same. More specifically, polylactic acid and polypropylene are blended using a specific dispersant to polylactic acid excellent in biodegradability, and a specific method. By producing non-woven fabrics by spinning under conditions, the polylactic acid blend non-woven fabrics that can easily reduce carbon emissions can reduce the friction coefficient of the non-woven fabric surface, improve flexibility, and improve product quality The present invention relates to a polylactic acid blend nonwoven fabric having improved properties and a method for producing the same.

  Plant-derived polymers that can be obtained from biomass and regenerated from biomass with less environmental burden due to environmental pollution problems caused by waste polymers and soaring crude oil prices, which increase geometrically with technological development and improvement in quality of life. Materials are attracting attention. In particular, as environmental pollution has recently become more serious, biodegradable polymers that can be naturally degraded in soil or landfills have attracted attention.

  Among these polymers, aliphatic polyester polymers have been most actively studied as biodegradable polymers because of their excellent processability and easy adjustment of degradation characteristics. In the case of (polylactic acid: PLA), the market has a scale of 100,000 tons all over the world, and the scope of application extends to fields where general plastics such as food packaging materials and containers and electronic product cases were used. The current situation is expanding. Until now, the main use of polylactic acid resin has been generally used in disposable products using the biodegradable properties of polylactic acid, such as food containers, wraps, films and the like.

  Recently, research on blending pon-lactic acid and polypropylene is in progress. However, when the polylactic acid is blended with polypropylene, the amount of general-purpose resin derived from petroleum raw materials can be reduced. In particular, the amount of petroleum fuel used has been reduced, and the method has been attracting attention as a method for reducing the environmental load by reducing the generation of carbon dioxide and the heat of combustion during disposal. In particular, in the case of polypropylene that is most frequently used for disposable hygiene products, the amount of carbon dioxide generated when burning 1 ton of polypropylene is 3,200 kg, whereas in the case of polylactic acid, 1,830 kg. However, it remains at 57% of the level of polypropylene, which can be said to be extremely advantageous.

  However, in spite of the advantageous aspects described above, when polylactic acid and polypropylene are blended, the dispersibility of polylactic acid and polypropylene is not sufficient, and heat resistance and mechanical properties cannot be improved. In order to solve such problems, a method of blending polylactic acid and a thermoplastic resin other than polylactic acid and a blend of polylactic acid and polymethyl methacrylate are disclosed. In the polypropylene that is incompatible with polylactic acid, there is a limit to improving the compatibility. When blending and spinning polylactic acid and a general-purpose resin, depending on the production process, the die becomes severe. Problems such as pressure rise and yarn breakage occurred, and it could not be used practically, but this has good compatibility between polylactic acid and general-purpose resin Even if, as long as the spinning manufacturing process is not backed means inability to produce nonwoven fabric. Therefore, research for solving the above-mentioned problems has been continued, and Patent Document 1 is intended to provide a disposable absorbent product having a biodegradable nonwoven material having fluid treatment characteristics, which is thermoplastic. In order to improve the production and processing of the composition, the use of a compatibilizing agent and the production of fibers using polylactic acid, polypropylene and compatibilizing agent are disclosed. The nonwoven fabric having biodegradability and low carbon emission characteristics by blend spinning is a nonwoven fabric produced by blend spinning of polylactic acid and polypropylene. The weight of polylactic acid in the total weight of the polymer mixture for blending is 10 to 80% by weight, the weight of polypropylene is 10 to 89% by weight, the weight of the dispersant is 1 to 10% by weight, and the nonwoven fabric Total weight is characterized in that it is made of a 10～100Gsm, nonwoven and a manufacturing method thereof having biodegradability and low carbon emissions characteristics by blending spinning of the polylactic acid is disclosed.

  However, the above-mentioned conventional polylactic acid blended nonwoven fabrics are mainly focused on improving spinnability by resin mixing properties. Regarding the improvement of mechanical or physical properties of these blended nonwoven fabrics, I have not recognized it at all, and there is almost no research on this.

Korean Patent Publication No. 2002-0029110 Korean Patent Publication No. 2012-0063063

  Therefore, the present invention has been made in view of the above-mentioned conventional technical problems, and its purpose is to improve the compatibility between polylactic acid and a general-purpose resin and to produce it by spinning. Non-woven fabrics with improved physical properties and reduced carbon emissions. Polylactic acid blended nonwoven fabrics with excellent flexibility, which is the physical property of these manufactured nonwoven fabrics, and used in various applications, with improved commercial properties. It is to provide.

  Another object of the present invention is to provide a method for more easily producing a nonwoven fabric having excellent physical properties as described above.

  In addition to the above-described specific objectives, the present invention is based on such objectives and the general technique of the present specification, and achieves other objectives easily derived by those skilled in the art. Objective.

  The above-described object of the present invention is to apply a specific dispersant that improves the compatibility when blending polylactic acid and polypropylene, and to add a softening agent at a certain ratio, so that polylactic acid is incorporated into the polypropylene. This was achieved by finding that the non-woven fabric was excellent in spinnability and the flexibility of the produced non-woven fabric could be remarkably improved by adjusting the manufacturing process conditions during spinning.

  In order to achieve the above-described object, the polylactic acid blend nonwoven fabric having improved flexibility according to the present invention is a nonwoven fabric manufactured by blend spinning of polylactic acid and polypropylene, in the total weight of the polymer mixture for blending. The weight of the polylactic acid is 10 to 80% by weight, the weight of the polypropylene is 10 to 89% by weight, the weight of the dispersant is 1 to 7% by weight, and the weight of the softening agent is 1 to 3% by weight. The total weight of the nonwoven fabric is 10 to 100 gsm.

  According to another aspect of the present invention, the softener is an erucamide softener.

  According to still another aspect of the present invention, the erucic acid amide is stearyl erucic acid amide or erucyl erucic acid amide.

  According to still another aspect of the present invention, the dispersant includes a hydrophilic part miscible with the polylactic acid polymer and a hydrophobic part miscible with the polypropylene polymer.

  In order to achieve the other objects described above, the method for producing a polylactic acid blend nonwoven fabric with improved flexibility according to the present invention is a method for producing a nonwoven fabric by blend spinning of polylactic acid and polypropylene, wherein the production method comprises blending. 10 to 80% by weight of polylactic acid, 10 to 89% by weight of polypropylene, 1 to 7% by weight of dispersant, and 1% by weight of softener in the total weight of the polymer mixture for The polylactic acid and polypropylene as a substantially continuous phase composed of ˜3 wt% are dispersed by uniformly dry-mixing the polylactic acid in the polypropylene resin using a dispersant. Forming a dry mixture, and blending the dry mixture of the thermoplastic composition, preferably by stirring, scraping, or other methods, to form a polylactic acid polymer, Mixing the propylene polymer and the dispersant effectively and uniformly to form a homogeneous dry mixture, and melt blending the dry mixture in an extruder to produce a polylactic acid polymer, a polypropylene polymer, and A step of effectively and uniformly mixing a dispersant to form a homogeneous molten mixture, and a step of spinning the molten mixture to form a web and thermocompression bonding to form a nonwoven fabric, The total weight of the nonwoven fabric is 10 to 100 gsm.

  According to another configuration of the present invention, the polylactic acid is a polylactic acid having a melt flow index (MFI: Melt Flow Index, 210 ° C.) of 15 to 30 g / 10 min.

  According to the present invention, by adding a specific softening agent at a certain ratio, the coefficient of friction of the surface of the nonwoven fabric is lowered, the flexibility is improved, and in addition to the low carbon emission characteristics of the conventional polypropylene / polylactic acid nonwoven fabric. In addition, it solves the disadvantage of inflexibility due to the hard properties peculiar to polylactic acid, and furthermore, by mixing and spinning with a dispersant, by specifying and adjusting the manufacturing process conditions, polylactic acid and polypropylene are uniform To improve the productivity and solve the above-mentioned conventional problems.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

  Prior to elaborating the present invention, the polylactic acid used throughout the specification of the present invention is first defined as polylactic acid is produced by polymerization of lactic acid or lactide, The term “polylactic acid” used in the present invention means a polymer produced by polymerization of lactic acid or lactide. Lactic acid may be polymerized using any known polymerization method such as polycondensation or ring-opening polymerization. In the polycondensation process, for example, L-lactic acid, D-lactic acid, or mixtures thereof are applied directly to dehydration-polycondensation. In the ring-opening polymerization process, lactide, a cyclic dimer of lactic acid, is applied to the polymerization with the aid of polymerization regulators and catalysts. Lactide may include L-lactide, D-lactide, and DL-lactide (also called meso-lactide, a condensate of L-lactic acid and D-lactic acid). Each said lactide (ie L-lactide, D-lactide, and DL-lactide) is a dimer. That is, they consist of two lactic acid units. Because of its chiral center, lactic acid has two different stereochemical isomers, namely the R and S isomer forms. D-lactide contains two R isomers, L-lactide contains two S isomers, and meso-lactide contains R and S isomers. Different isomers are mixed and polymerized as necessary to obtain polylactic acid having any required composition and crystallinity described below. Moreover, the molecular weight of polylactic acid can be increased using a small amount of chain extender (for example, a diisocyanate compound, an epoxy compound, or an acid anhydride described later). Preferably, the polylactic acid has a weight average molecular weight of about 60,000 to 1,000,000.

Suitable polylactic acid polymers that can be used in the present invention include, but are not limited to, Natureworks (registered trademark) in Minneapolis, Minnesota, USA, as one specific example. This is commercially available. Other suitable polylactic acid polymers are commercially available from Biomer, Inc. of Kyling, Germany, from BIOMER ^™ L9000 or Mitsui Chemicals (RACEA ^™ ). It is available. Still other suitable polylactic acids are U.S. Pat. Nos. 4,797,468, 5,470,944, 5,770,682, and 5,821,327, which are incorporated herein by reference. 5,880,254, and 6,326,458 can be used.

  Also, the polylactic acid melt flow index is forced through an extrusion flow meter orifice (0.0825 inch diameter) when applied to a load of 2160 g per 10 minutes at any temperature (eg, 210 ° C.). The polymer weight (g) measured by ASTM test method D1238-E. Polylactic acid also typically has a melting point of about 100 ° C to 240 ° C, in some embodiments about 120 ° C to 220 ° C, and in some embodiments about 140 ° C to 200 ° C. Such low melting point polylactic acid is useful in that they are biodegraded at high speed. The glass transition temperature (“Tg”) of polylactic acid is also relatively low so as to improve the solubility and processability of the polymer. For example, the Tg may be about 80 ° C. or less, in some embodiments about 70 ° C. or less, and in some embodiments about 65 ° C. or less. As described in detail below, both melting point and glass transition temperature can be determined using a differential scanning calorimeter (“DSC”) according to ASTM D-3417.

  The polylactic acid polymer is usually produced by a polymerization reaction of lactic acid. However, it will be understood by those skilled in the art that chemically equivalent materials can be similarly produced by a polymerization reaction of lactide. For this reason, the term “polylactic acid polymer” used in the present specification is intended to indicate a polymer produced by a polymerization reaction of lactic acid or lactide.

  In general, the polylactic acid polymer is preferably present in the thermoplastic composition in an amount effective to produce a thermoplastic composition exhibiting suitable properties (eg, a polypropylene polymer). The polylactic acid polymer is present in the thermoplastic composition in an amount of about 10 to 80% by weight, preferably about 15 to 70% by weight, more preferably about 20 to 60% by weight, All weight percentages are based on the total weight of polylactic acid polymer, polypropylene polymer, and dispersant present in the thermoplastic composition. In order for the thermoplastic composition to be substantially spun to form a nonwoven, the composition ratio of the three components in the thermoplastic composition must be maintained because the polypropylene polymer must be in a substantially continuous phase. is important. The approximate limit of the component ratio may be determined based on the density of the component. The component density is converted to volume (each component is estimated to be 100 g), the component volumes are added together to determine the volume of the entire thermoplastic composition, the weight average of the components is calculated, and the poly An approximate minimum ratio of each component required to produce a thermoplastic composition in which the lactic acid polymer occupies most of the volume is obtained.

  Polypropylene polymers are known in the art as resins belonging to polyolefin polymers. Any polyolefin that can be produced as an article, such as spunbond filaments, would be suitable for use in the present invention. Polypropylene may be high or low density, and may be a linear or branched polymer. Polypropylene production methods are known to those skilled in the art.

  The polypropylene is generally naturally hydrophobic. As used herein, the term “hydrophobic” refers to a material having a contact angle of water in air of at least 90 degrees. On the other hand, the term “hydrophilic” in the present specification refers to a material having a contact angle of water in air of less than 90 degrees. According to the present invention, the measured contact angle can be obtained from the literature [Robert J. et al. Good and Robert J. et al. Stromberg, Ed. , In 'Surface and Colloid Science-Experimental Methods', Vol. II, (Plenum Press, 1979), pages 63-70].

  In general, both polylactic acid polymer and polypropylene are preferably melt processable. Thus, the polylactic acid polymer and polypropylene are about 1 g per 10 minutes to about 200 g per 10 minutes, preferably about 10 g per 10 minutes to about 100 g per 10 minutes, more preferably about 20 g per 10 minutes It preferably exhibits a melt flow rate of about 40 grams per 10 minutes. The melt flow rate of the material can be determined by ASTM test method D1238-E, which is cited herein as a reference.

  The polymers are not chemically the same and are therefore somewhat immiscible with each other, which tends to adversely affect the processing of the polymer mixture, improving the processability of polylactic acid polymers and polypropylene polymers It became clear that it was preferable. For example, polylactic acid polymers and polypropylene polymers are sometimes difficult to mix effectively themselves and are difficult to produce as essentially uniform mixtures. In general, it has been found preferable to use a dispersant to assist in the effective production of polylactic acid and polypropylene polymers and processing into a single thermoplastic composition.

  Suitable dispersants that can be used in the present invention include a hydrophilic portion that is miscible with the polylactic acid polymer and a hydrophobic portion that is miscible with the polypropylene polymer. These hydrophilic and hydrophobic moieties generally exist as separate blocks, and the overall dispersant structure may be a diblock or random block. It is preferred that the dispersant initially acts as a plasticizing material to improve the manufacturing and processing of the thermoplastic composition. Next, among the nonwoven materials of the present invention, which is a material processed from a thermoplastic composition, the dispersant becomes a surfactant by changing the contact angle of water in the air of the processed material. It is preferable to act. The hydrophobic portion of the dispersant may be polystyrene, but is not limited thereto. The hydrophilic portion of the dispersant may contain ethylene oxide, ethoxylate, glycol, alcohol, or any mixture thereof. A suitable dispersant component is preferably a styrene-ethylene-butylene-styrene block copolymer component.

  In general, it is preferred that the dispersant be present in the thermoplastic composition in an amount effective to produce a thermoplastic composition exhibiting suitable properties. A minimal amount of dispersant is required to achieve effective blending and processing with other components of the thermoplastic composition. Too much dispersant will result in processing problems for the thermoplastic composition. The dispersant is advantageously present in the thermoplastic composition in an amount of about 1-7% by weight, preferably about 1.5-6% by weight, more preferably about 2-5% by weight, At this time, all weight% is based on the total weight of the polylactic acid polymer, the polypropylene polymer, and the dispersant present in the thermoplastic composition.

According to a preferred embodiment of the present invention, although softening agent 1-3% by weight is mixed, the _{softener, CH 3 (CH 2) 7} CH = CH (CH 2) 11 erucamide CONH ₂ It is preferable to use a system softener, and examples of the erucic acid amide include stearyl erucic acid amide and erucyl erucic acid amide.

  Thus, the nonwoven fabric is improved in biodegradability, low carbon emission characteristics and flexibility by blend spinning of polylactic acid according to the present invention, and the softener is preferably 1 to 3% by weight. If the content of the agent is less than 1%, the effect of lowering the friction coefficient of the surface of the nonwoven fabric is insignificant. If it exceeds 3%, the effect of lowering the friction coefficient is good, but the nonwoven fabric passes through the belt. This is not preferable because slip occurs and causes a problem in the process.

  The main components of the thermoplastic composition for the production of the nonwoven fabric according to the present invention have been described above, but the thermoplastic composition is not limited thereto, and other components that do not adversely affect the preferred properties of the resulting nonwoven fabric. May be included. Examples of materials used as additional components include pigments, antioxidants, stabilizers, surfactants, waxes, flow promoters, solid phase solvents, plasticizers, nucleating agents, particulates, and thermoplastic compositions A material added to improve the workability of the object may be included without limitation. When the additional component is included in the thermoplastic composition, the additional component is advantageously less than about 5% by weight, more advantageously less than about 3% by weight, preferably about 1% by weight. Preferably, all weight percents are based on the total weight of polylactic acid polymer, polypropylene, dispersant, and softener present in the thermoplastic composition.

  The thermoplastic composition used in the present invention is generally obtained in the form of a mixture of a polylactic acid polymer, a polypropylene polymer, a dispersant, a softening agent, and any additional components. The polylactic acid polymer forms a substantially discontinuous phase surrounded within the continuous phase of the substantially polypropylene polymer. In order to achieve suitable properties of the thermoplastic composition, it is preferred that the polylactic acid polymer, polypropylene polymer, dispersant, and softener are maintained substantially unreacted with each other. For this reason, each of the polylactic acid polymer, polypropylene, dispersant, and softener remains as a separate component of the thermoplastic composition. Also, the polypropylene polymer forms a substantially continuous phase, and the polylactic acid polymer forms a substantially discontinuous phase, wherein the continuous phase of the polypropylene polymer is substantially within its structure. Surrounds the polylactic acid polymer.

  In one embodiment of the invention, a polylactic acid polymer, a polypropylene polymer, a dispersant, a softener are dry mixed together to form a dry mixture of the thermoplastic composition, and then the dry mixture of the thermoplastic composition. Is preferably stirred, agitated, or otherwise blended to effectively and uniformly mix the polylactic acid polymer, polypropylene polymer, dispersant, and softener to provide an essentially homogeneous dry mixture. Form. The dry mixture is then melt blended, eg, in an extruder, to effectively and uniformly mix the polylactic acid polymer, polypropylene polymer, and dispersant to form an essentially homogeneous molten mixture. .

  The manufacturing method of the multicomponent fiber manufactured from the thermoplastic composition mentioned above is demonstrated. Polymer melt spinning involves the production of structures of continuous filaments, such as spunbond or meltblown, and discontinuous filaments, such as staples and shortcut fibers. In order to produce spunbond or meltblown fibers, the thermoplastic composition is typically extruded and fed into a dispensing system, where the thermoplastic composition is introduced into the spinneret plate. The spun fibers are subsequently cooled, solidified, drawn with an aerodynamic system and formed into a conventional nonwoven. On the other hand, rather than directly forming into a non-woven structure to produce shortcut or staple fibers, the spun fibers are cooled and solidified and generally stretched to the diameter of the intermediate filaments with a mechanical roll system And converge. The fiber is then “cool drawn” to a suitable final fiber diameter at a temperature below its softening temperature, crimped, or shape adhered and cut to a suitable fiber diameter.

  In the cooling step for drawing the extruded thermoplastic composition and / or fiber, it is preferable to use a cooling means that does not contain water since the composition does not contain a water-soluble component. Cooling is usually done by blowing air at or below ambient temperature over the extruded polymer. At this time, cooling temperature becomes like this. Preferably it is 10-20 degreeC, More preferably, it is 13-18 degreeC.

  Polylactic acid materials often undergo thermal shrinkage during the thermal processing process in the latter half of the process. Heat shrinkage is caused by heat-induced chain relaxation of the polymer segments, mainly in the amorphous phase and the imperfect crystalline phase. To overcome these problems, maximize the crystallization of the material prior to the bonding step so that the thermal energy melts directly rather than allowing chain relaxation and incomplete crystalline structure realignment. It is preferable to do. A typical solution to such problems is to perform a heat effect treatment on the material. For this reason, when the manufactured material, e.g., the fiber, reaches the bonding roll and undergoes a thermosetting process, the fiber is already fully or very much oriented and therefore does not substantially shrink. The present invention eliminates the need for such additional processing steps because of the multicomponent fiber morphology. As mentioned above, polypropylene generally provides a reinforced structure that minimizes the expected thermal shrinkage of polylactic acid.

  As described above, the method for producing a nonwoven fabric by blend spinning of polylactic acid and polypropylene according to the present invention uniformly disperses polylactic acid and polypropylene as a substantially continuous phase in a polypropylene resin using a dispersant. By doing so, it is possible to produce a nonwoven fabric that can be substantially decomposed but is easily processed into a nonwoven structure that exhibits the effective mechanical and liquid processing properties of the fiber.

  According to a preferred embodiment of the present invention, in a method of producing a nonwoven fabric by polylactic acid / polypropylene blend spinning, polylactic acid and a dispersant are extruded at a constant ratio together with polypropylene using a dosing system for metering raw materials. In this case, the charging rate of polylactic acid is advantageously about 10 to 80% by weight, preferably about 15 to 70% by weight, and more preferably about 20 to 60% by weight as described above. The amount is good. If the feed rate of polylactic acid is less than 10% by weight, there is a problem that the carbon reduction efficiency is low, and if it exceeds 90% by weight, there is a problem that a large amount of auxiliary material is charged in normal equipment. There is a problem of rising costs, which is not preferable.

  The polylactic acid / polypropylene blend mixture containing the dispersant is a thermoplastic or spinnable polymer. The term “mixture” as used herein includes a heterogeneous mixture of two or more physically separate polymers, such as a homogeneous mixture of two or more polymers or bicomponent fibers. Next, a polylactic acid / polypropylene blend mixture containing a dispersant is spun, and the spun filament is solidified by cooling air sprayed from a honeycomb-shaped chamber, and is blown from the top and sucked from the bottom of the conveyor belt. The web is formed by being stretched by the pressure of the air to be laid and laminated at a constant weight on the conveyor belt. The web may include a single layer (meltblown layer M or spunbond layer S), a composite of two layers (SS or SM), or a composite layer of three or more layers (SMS, SMMS, SSMMS, SSMMSS web). Good. Specific webs vary greatly in weight (gsm), and such weight changes can be adjusted by layer-by-layer discharge and belt speed being transported. Finally, the assembled web is thermally bonded to provide mechanical properties and form stability. Although the bonding area is not limited, the configuration of the calender roll is that one side is usually composed of an embossing roll surface having a bonding area of 10 to 20% by weight, and the other side is a roll having a smooth surface, The web accumulated in multiple layers is formed into a sheet while passing through the roll. Well known in the art for bonding integrated webs, such as a process selected from the group consisting of chemical bonding (resin bonding), water flow bonding, and needle punching as well as thermal bonding. The long fiber nonwoven web can be bonded to form a nonwoven by any process. Preferably, thermal bonding may be used.

  Hereinafter, the nonwoven fabric of the present invention will be specifically described with reference to examples. It is usual in the art that these examples are merely presented for explaining the present invention more specifically, and that the scope of the present invention is not limited by these examples. It will be obvious to those who have knowledge.

  In the following examples and comparative examples, fibers were produced using various amounts of polylactic acid, polypropylene, a dispersant, and a softening agent. These polylactic acid polymers (PLA) were manufactured in Minnesota, USA. Obtained from Natureworks, Minneapolis, the melt flow index is 15-30 g / 10 min, and the polypropylene polymer (PP) is obtained from Honam Petrochemicals under the trade name SFR-171H, and the melt flow index is 35 g / 10 min, having a melting temperature of about 160 ° C., and the dispersant is obtained by using the trade name DYNARON 8630P from JSR Corporation located in Tsukiji, Chuo-ku, Tokyo, Japan. In a method for producing a nonwoven fabric using this, a polylactic acid and a dispersant are used as a dosing system for measuring raw materials. Is used to transfer polypropylene to a extruder at a constant ratio according to the respective examples and comparative examples to spin the mixture, and the spun filaments are solidified by cooling air injected from a honeycomb-shaped chamber, After stretching by the pressure of air blown from the top and air sucked from the bottom of the conveyor belt, a web was formed by laminating on the conveyor belt with a constant weight, and then thermal bonding was performed to produce a nonwoven fabric.

Example 1
Polylactic acid 20% by weight, dispersant 3% by weight, softening agent 1% by weight, polypropylene resin 76% by weight, melt-spun and fiberized, stretched on a porous conveyor belt, base weight is 40 gsm A certain polylactic acid / polypropylene non-woven fabric was produced, and the physical properties of the produced non-woven fabric were measured and are shown in Table 1 below.

Example 2
A nonwoven fabric was produced in the same manner as in Example 1 except that 20% by weight of polylactic acid, 3% by weight of a dispersant, 3% by weight of a softening agent, and 74% by weight of a polypropylene resin were charged, and the properties of the produced nonwoven fabric were measured. The results are shown in Table 1 below.

Comparative Example 1
A nonwoven fabric was produced in the same manner as in Example 1 except that 20% by weight of polylactic acid, 3% by weight of a dispersant, and 77% by weight of a polypropylene resin were charged, and the physical properties of the produced nonwoven fabric were measured. It was shown to.

Comparative Example 2
A nonwoven fabric was produced in the same manner as in Example 1 except that 20% by weight of polylactic acid, 3% by weight of a dispersant, 0.5% by weight of a softening agent, and 76.5% by weight of a polypropylene resin were charged. The physical properties were measured and shown in Table 1 below.
Comparative Example 3
A nonwoven fabric was produced in the same manner as in Example 1 except that 20% by weight of polylactic acid, 3% by weight of a dispersant, 5% by weight of a softening agent, and 72% by weight of a polypropylene resin were charged, and the physical properties of the produced nonwoven fabric were measured. The results are shown in Table 1 below.

Experimental Example The respective physical properties of the nonwoven fabrics produced by the above-described examples and comparative examples were evaluated as follows.

(1) Weight per unit area (weight: g / m ² ): Measured by the method of ASTM D 3776-1985.
(2) Tensile strength: Using a measuring instrument of a tensile strength and elongation machine (Instron), a test piece having a width of 5 cm and a distance of 10 cm was pulled at a tensile speed of 500 mm / min according to the KSK 0520 method. The load was determined.
(3) Tensile elongation: The elongation at the maximum elongation measured by the method of (2) was determined.
(4) Flexibility (coefficient of friction): When the coefficient of friction measurement equipment is operated using the method of KS M 3009, the measuring device automatically tilts, the plate slides downward, and stops when the sensor is pressed. At this time, the angle value in the stopped state is converted.

The technical idea of the present invention has been described in detail in the preferred embodiments. However, it should be noted that the above-described embodiments are for explanation, not for limitation. Don't be. It will be apparent to those skilled in the art that various modifications and variations can be made within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the appended claims. .

Claims (6)

In the nonwoven fabric produced by blend spinning of polylactic acid and polypropylene,
In the total weight of the polymer mixture for blending, the weight of polylactic acid is 10 to 80% by weight, the weight of polypropylene is 10 to 89% by weight, and the weight of the dispersant is 1 to 7% by weight. And a softening agent having a weight of 1 to 3% by weight, and the total weight of the nonwoven fabric is 10 to 100 gsm.   2. The polylactic acid blend nonwoven fabric with improved flexibility according to claim 1, wherein the softener uses an erucamide softener. 3.   The polylactic acid blend nonwoven fabric with improved flexibility according to claim 2, wherein the erucic amide is stearyl erucic amide or erucyl erucic amide.   The polylactic acid with improved flexibility according to claim 1, wherein the dispersant includes a hydrophilic part miscible with the polylactic acid polymer and a hydrophobic part miscible with the polypropylene polymer. Blended nonwoven fabric. In a method for producing a nonwoven fabric by blend spinning of polylactic acid and polypropylene,
In the production method, the total weight of the polymer mixture for blending is 10-80% by weight of polylactic acid, 10-89% by weight of polypropylene, 1-7% by weight of dispersant, By comprising 1 to 3% by weight of a softening agent and dispersing polylactic acid and polypropylene as a substantially continuous phase by uniformly dry-mixing polylactic acid in a polypropylene resin using a dispersant. Forming a dry mixture of the thermoplastic composition;
The dry mixture of the thermoplastic composition is advantageously blended by stirring, scratching or other methods to effectively and uniformly mix the polylactic acid polymer, polypropylene polymer, and dispersing agent to achieve homogeneity. Forming a dry mixture,
Melt blending the dry mixture in an extruder and mixing the polylactic acid polymer, polypropylene polymer, and dispersant effectively and uniformly to form a homogeneous melt mixture;
Spinning the molten mixture to form a web, thermocompression bonding to form a nonwoven fabric, and
A method for producing a polylactic acid blend nonwoven fabric with improved flexibility, wherein the total weight of the nonwoven fabric is 10 to 100 gsm. 6. The polylactic acid with improved flexibility according to claim 5, wherein the polylactic acid is a polylactic acid having a melt flow index (MFI: Melt Flow Index, 210 ° C.) of 15 to 30 g / 10 minutes. A method for producing a blended nonwoven fabric.